The overall objectives of this research project are to investigate the development of auditory attention to speech by hearing-impaired infants and children and to assess how the segmental and prosodic characteristics of maternal speech input are affected by infants'hearing status. In Specific Aim 1, we will investigate the development of attention to speech input by hearing-impaired infants with hearing aids and cochlear implants. The Babytalk Research Laboratory at Indiana University School of Medicine employs established paradigms for studying speech perception and language development in both normal-hearing and hearing-impaired infants. In several related procedures that have been used extensively by developmental scientists, infants are seated in a sound booth and are presented with auditory and visual signals on a TV monitor. Infants'looking times to the visual signal in response to the various auditory stimuli will be measured as an index of their attentional preferences. In Specific Aim 2, we will assess the segmental, prosodic, and structural characteristics of maternal speech to infants with and without hearing loss, and document how this changes over time. To address this issue, mothers'speech to infants will be digitally recorded and the acoustic-phonetic and perceptual characteristics of this speech will be evaluated in a series of studies. Finally, in Specific Aim 3, we will determine how hearing-impaired infants'attentional preferences for speech input and aspects of their mothers'speech are related to later clinical assessments of speech-language skills at 1 to 4 years of age. The proposed research addresses fundamental theoretical and clinical issues regarding the effects of early sensory and linguistic experience on speech-language outcome. It also addresses the benefit of very early amplification via hearing aids and cochlear implants on hearing-impaired infants'speech and language development. The findings from this research project will provide clinicians and researchers with new knowledge about the linguistic development of children with hearing impairment that may be used to develop early interventions to maximize successful verbal communication skills in infants and children with hearing impairment.